Dissolution Kinetics of Cubic Tricalcium Aluminate Measured by Digital Holographic Microscopy
Dissolution Kinetics of Cubic Tricalcium Aluminate Measured by Digital Holographic Microscopy
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DOI：
10.1021/acs.langmuir.7b02400
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发表时间：
2017-09-26
期刊：
影响因子：
3.9
通讯作者：
Bullard, Jeffiey W.
中科院分区：
文献类型：
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作者：
Brand, Alexander S.;Bullard, Jeffiey W.
采用原位数字全息显微术研究了多晶立方铝酸三钙（C（3）A-c）的溶解通量。表面溶解的速率随时间和空间位置而变化很大。这意味着一个统计分布的通量，但通过使用流动的解决方案，并通过减少溶液中的水活度获得了一个近似稳定状态的中值速率。从高度结晶的C（3）A-c的溶解通量取决于水活度，上升到经验推导的指数5.2，并外推到纯水中的中位通量为-2.1 μ mol m（-2）s（-1），四分位距为3.2 μ mol m（-2）s（-1）。来自结晶度较低的C（3）A-c源的通量的经验水活度指数为4.6，在纯水中的外推中值通量仅为-1.4 μ mol m（-2）s（-1），四分位距为1.9 μ mol m（-2）s（-1）。这些数据表明，C（3）A-c的整体溶解速率从一个来源到另一个来源可以变化至少30%，并且由于结构特征的不均匀空间分布（即，结晶度、化学杂质和缺陷）。
In situ digital holographic microscopy is used to characterize the dissolution flux of polycrystalline cubic tricalcium aluminate (C(3)A-c). The surface dissolves at rates that vary considerably with time and spatial location. This implies a statistical distribution of fluxes, but an approximately steady-state median rate was obtained by using flowing solutions and by reducing the water activity in the solution. The dissolution flux from highly crystalline C(3)A-c depends on the water activity raised to an empirically derived exponent of 5.2 and extrapolates to a median flux of - 2.1 mu mol m(-2) s(-1) in pure water with an interquartile range of 3.2 mu mol m(-2) s(-1). The flux from a less crystalline source of C(3)A-c has an empirical water activity exponent of 4.6 and an extrapolated median flux of only -1.4 mu mol m(-2) s-1 in pure water with an interquartile range of 1.9 mu mol m(-2) s(-1). These data suggest that the bulk dissolution rate of C(3)A-c can vary by at least 30% from one source to another and that variability in the local rate within a single material is even greater because of the heterogeneous spatial distribution of structural characteristics (i.e., degree of crystallinity, chemical impurities, and defects).